Grain Mustard and Tarragon Butter

• 250 g (9 oz) unsalted butter (softened at room temperature)
• 20 g (¾

Place the butter in an electric mixer bowl, attach the whisk, and whisk on high speed until light and fluffy. Add the mustards and whisk on medium to combine. Season with the cayenne pepper, add the soy and mirin, and continue to whisk until well combined.

Using a spatula, fold the herbs through the mixture and then scrape into a clean container. Set aside at room temperature, until req